1. Each restricted stock unit ("RSU") represents the right to receive one share of common stock, $0.001 par value per share (the "Common Stock"), of Casa Systems, Inc. (the "Company") upon vesting, subject to the reporting person's continued service relationship with the Company and the other terms and conditions set forth in the applicable RSU agreement. In the sole discretion of the Company's board of directors, the Company may, with respect to any applicable vesting date, deliver to the reporting person Common Stock or cash having a fair market value equal to the number of shares of Common Stock underlying the portion of the RSU that vested on such date, payable within 30 days of the vesting date, less applicable taxes.

2. Scheduled to vest over four years, with 25% of the shares underlying the award vesting on January 1, 2020, and 25% of the shares underlying the award vesting at the end of each successive one-year period thereafter.

Remarks:

/s/ Jerry Guo, attorney-in-fact

02/07/2019

** Signature of Reporting Person

Date

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person,
see
Instruction
4
(b)(v).